content: /* Copyright (C) 2016-2018 Alibaba Group Holding Limited
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  
      http://www.apache.org/licenses/LICENSE-2.0
  
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  ==============================================================================*/
  
  // Protocol Buffers - Google's data interchange format
  // Copyright 2014 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf.nano;
  
  
  /**
   * A custom version of {@code android.util.SparseArray} with the minimal API
   * for storing {@link FieldData} objects.
   *
   * <p>This class is an internal implementation detail of nano and should not
   * be called directly by clients.
   *
   * Based on {@code android.support.v4.util.SpareArrayCompat}.
   */
  public final class FieldArray implements Cloneable {
      private static final FieldData DELETED = new FieldData();
      private boolean mGarbage = false;
  
      private int[] mFieldNumbers;
      private FieldData[] mData;
      private int mSize;
  
      /**
       * Creates a new FieldArray containing no fields.
       */
      FieldArray() {
          this(10);
      }
  
      /**
       * Creates a new FieldArray containing no mappings that will not
       * require any additional memory allocation to store the specified
       * number of mappings.
       */
      FieldArray(int initialCapacity) {
          initialCapacity = idealIntArraySize(initialCapacity);
          mFieldNumbers = new int[initialCapacity];
          mData = new FieldData[initialCapacity];
          mSize = 0;
      }
  
      /**
       * Gets the FieldData mapped from the specified fieldNumber, or <code>null</code>
       * if no such mapping has been made.
       */
      FieldData get(int fieldNumber) {
          int i = binarySearch(fieldNumber);
  
          if (i < 0 || mData[i] == DELETED) {
              return null;
          } else {
              return mData[i];
          }
      }
  
      /**
       * Removes the data from the specified fieldNumber, if there was any.
       */
      void remove(int fieldNumber) {
          int i = binarySearch(fieldNumber);
  
          if (i >= 0 && mData[i] != DELETED) {
              mData[i] = DELETED;
              mGarbage = true;
          }
      }
  
      private void gc() {
          int n = mSize;
          int o = 0;
          int[] keys = mFieldNumbers;
          FieldData[] values = mData;
  
          for (int i = 0; i < n; i++) {
              FieldData val = values[i];
  
              if (val != DELETED) {
                  if (i != o) {
                      keys[o] = keys[i];
                      values[o] = val;
                      values[i] = null;
                  }
  
                  o++;
              }
          }
  
          mGarbage = false;
          mSize = o;
      }
  
      /**
       * Adds a mapping from the specified fieldNumber to the specified data,
       * replacing the previous mapping if there was one.
       */
      void put(int fieldNumber, FieldData data) {
          int i = binarySearch(fieldNumber);
  
          if (i >= 0) {
              mData[i] = data;
          } else {
              i = ~i;
  
              if (i < mSize && mData[i] == DELETED) {
                  mFieldNumbers[i] = fieldNumber;
                  mData[i] = data;
                  return;
              }
  
              if (mGarbage && mSize >= mFieldNumbers.length) {
                  gc();
  
                  // Search again because indices may have changed.
                  i = ~ binarySearch(fieldNumber);
              }
  
              if (mSize >= mFieldNumbers.length) {
                  int n = idealIntArraySize(mSize + 1);
  
                  int[] nkeys = new int[n];
                  FieldData[] nvalues = new FieldData[n];
  
                  System.arraycopy(mFieldNumbers, 0, nkeys, 0, mFieldNumbers.length);
                  System.arraycopy(mData, 0, nvalues, 0, mData.length);
  
                  mFieldNumbers = nkeys;
                  mData = nvalues;
              }
  
              if (mSize - i != 0) {
                  System.arraycopy(mFieldNumbers, i, mFieldNumbers, i + 1, mSize - i);
                  System.arraycopy(mData, i, mData, i + 1, mSize - i);
              }
  
              mFieldNumbers[i] = fieldNumber;
              mData[i] = data;
              mSize++;
          }
      }
  
      /**
       * Returns the number of key-value mappings that this FieldArray
       * currently stores.
       */
      int size() {
          if (mGarbage) {
              gc();
          }
  
          return mSize;
      }
  
      public boolean isEmpty() {
          return size() == 0;
      }
  
      /**
       * Given an index in the range <code>0...size()-1</code>, returns
       * the value from the <code>index</code>th key-value mapping that this
       * FieldArray stores.
       */
      FieldData dataAt(int index) {
          if (mGarbage) {
              gc();
          }
  
          return mData[index];
      }
  
      @Override
      public boolean equals(Object o) {
          if (o == this) {
              return true;
          }
          if (!(o instanceof FieldArray)) {
              return false;
          }
  
          FieldArray other = (FieldArray) o;
          if (size() != other.size()) {  // size() will call gc() if necessary.
              return false;
          }
          return arrayEquals(mFieldNumbers, other.mFieldNumbers, mSize) &&
                  arrayEquals(mData, other.mData, mSize);
      }
  
      @Override
      public int hashCode() {
          if (mGarbage) {
              gc();
          }
          int result = 17;
          for (int i = 0; i < mSize; i++) {
              result = 31 * result + mFieldNumbers[i];
              result = 31 * result + mData[i].hashCode();
          }
          return result;
      }
  
      private int idealIntArraySize(int need) {
          return idealByteArraySize(need * 4) / 4;
      }
  
      private int idealByteArraySize(int need) {
          for (int i = 4; i < 32; i++)
              if (need <= (1 << i) - 12)
                  return (1 << i) - 12;
  
          return need;
      }
  
      private int binarySearch(int value) {
          int lo = 0;
          int hi = mSize - 1;
  
          while (lo <= hi) {
              int mid = (lo + hi) >>> 1;
              int midVal = mFieldNumbers[mid];
  
              if (midVal < value) {
                  lo = mid + 1;
              } else if (midVal > value) {
                  hi = mid - 1;
              } else {
                  return mid; // value found
              }
          }
          return ~lo; // value not present
      }
  
      private boolean arrayEquals(int[] a, int[] b, int size) {
          for (int i = 0; i < size; i++) {
              if (a[i] != b[i]) {
                  return false;
              }
          }
          return true;
      }
  
      private boolean arrayEquals(FieldData[] a, FieldData[] b, int size) {
          for (int i = 0; i < size; i++) {
              if (!a[i].equals(b[i])) {
                  return false;
              }
          }
          return true;
      }
  
      @Override
      public final FieldArray clone() {
          // Trigger GC so we compact and don't copy DELETED elements.
          int size = size();
          FieldArray clone = new FieldArray(size);
          System.arraycopy(mFieldNumbers, 0, clone.mFieldNumbers, 0, size);
          for (int i = 0; i < size; i++) {
              if (mData[i] != null) {
                  clone.mData[i] = mData[i].clone();
              }
          }
          clone.mSize = size;
          return clone;
      }
  }
  